For a cellular mobile communication system, a duplex mode refers to a multiplexing mode of an uplink and a downlink; and for a mobile communication device (a base station or a UE), a duplex mode refers to a multiplexing mode of transmission and reception links. Time Division Duplex (TDD) and Frequency Division Duplex (FDD) are two general duplex modes in transmission of radio communication, and both the TDD mode and the FDD mode are supported concurrently in a Long Term Evolution (LTE) system. In the TDD mode, uplink and downlink signals are transmitted respectively in an uplink and a downlink at different intervals of time; and in the FDD mode, uplink and downlink signals are transmitted respectively in an uplink and a downlink over different operating frequency bands. Reference can be made to FIG. 1 and FIG. 2 for a duplex mode, where FIG. 1 is a schematic principle diagram of a duplex mode, and FIG. 2 is a schematic diagram of time and frequency relationships in the general duplex modes, and in FIG. 2, T represents transmission and R represents reception.
For the general duplex modes adopted in a cellular system: in the TDD mode, uplink and downlink signals are transmitted respectively in an uplink and a downlink with a Guard Period (GP) therebetween over the same operating frequency band at different intervals of time; and in the FDD mode, uplink and downlink signals can be transmitted respectively in an uplink and a downlink with a Guard Band therebetween over different frequency carriers over different operating frequency bands at the same time.
In a general TDD cellular mobile communication system, a mobile communication device (including a base station or a UE) also operates in the TDD mode, and a transmission and reception changeover switch is required in the device; and in a general FDD cellular mobile communication system, a mobile communication device (including a base station or a UE) also operates in the FDD mode, and a transmission and reception duplex filter is required in the device.
In an LTE system, a frame structure adopted for the FDD mode differs from that for the TDD mode, and they will be described particularly below:
FIG. 3 is a schematic diagram of a frame structure of an LTE FDD system, and as illustrated in FIG. 3, a radio frame with a length of 10 ms includes ten sub-frames, each including two time slots of 0.5 ms in the frame structure of the LTE FDD system, where Ts represents a sampling interval.
FIG. 4 is a schematic diagram of a somewhat more complex frame structure of an LTE TDD system, and as illustrate in FIG. 4, a radio frame which is also with a length of 10 ms can include one or two special sub-frames divided into three time slots: a Downlink Pilot Time Slot (DwPTS), a GP and an Uplink Pilot Time Slot (UpPTS). A sub-frame 0, a sub-frame 5 and the DwPTS are always used for downlink transmission, and other sub-frames can be used for uplink transmission or downlink transmission as needed.
The lengths of the three time slots in a special sub-frame are configured as depicted in Table 1 below showing all configuration schemes of the region of a special sub-frame.
TABLE 1Configurations of a special sub-frame in an LTE TDD systemSequencenumber ofShort CPExtended CPconfigurationDwPTSGPUpPTSDwPTSGPUpPTS0 6592 · Ts21936 · Ts 2192 · Ts 7680 · Ts20480 · Ts 2560 · Ts119760 · Ts8768 · Ts20480 · Ts7680 · Ts221952 · Ts6576 · Ts23040 · Ts5120 · Ts324144 · Ts4384 · Ts25600 · Ts2560 · Ts426336 · Ts2192 · Ts 7680 · Ts17920 · Ts 5120 · Ts5 6592 · Ts19744 · Ts 4384 · Ts20480 · Ts5120 · Ts619760 · Ts6576 · Ts23040 · Ts2560 · Ts721952 · Ts4384 · Ts———824144 · Ts2192 · Ts———
For the structure of frame in the LTE TDD system, another important category of configurations are configurations of uplink and downlink sub-frames, and specific configuration schemes are as depicted in Table 2 below listing seven configurations, where D represents a sub-frame for downlink transmission, U represents a sub-frame for uplink transmission, and S represents a special sub-frame including three parts of DwPTS, GP and UpPTS.
TABLE 2Configurations of uplink and downlinksub-frames in an LTE TDD systemSequencenumber ofSwitchingSequence number of sub-frameconfigurationperiod012345678905 msDSUUUDSUUU15 msDSUUDDSUUD25 msDSUDDDSUDD310 ms DSUUUDDDDD410 ms DSUUDDDDDD510 ms DSUDDDDDDD65 msDSUUUDSUUD
A PCFICH (Physical Control Format Indicator Channel), a PDCCH (Physical Downlink Control Channel), PHICH (Physical HARQ Indicator Channel), PDSCH (Physical Downlink Shared Channel) and a PSS (Primary Synchronization Signal) can be transmitted in the DwPTS field, and a PRACH (Physical Random Access Channel) and SRS (Sounding Reference Signal) but neither a PUSCH (Physical Uplink Shared Channel) nor a PUCCH (Physical Uplink Control Channel) can be transmitted in the field UpPTS.
A drawback in the prior art lies in that a technical solution enabling a duplex mode of a UE to be known at the network side is absent so far in a communication system.